Spontaneous remission of primary hyperparathyroidism due to hemorrhagic infarction in the parathyroid adenoma

A 59-year-old man visited Kyoto University Hospital because of general malaise, polyuria, and polydipsia, The diagnosis of primary hyperparathyroidism was made based on hypercalcemia and an elevated circulating PTH level, A nodule was palpable in the left anterior neck, Two weeks later, the serum calcium level was normalized and his symptoms subsided, A temporary expansion, followed by reduction of the tumor size was observed by serial ultrasonography, Histology of the resected tumor showed central necrotic tissue, with some peripherally remaining glandular tissue, We report here a rare case of primary hyperparathyroidism with spontaneous remission due to hemorrhagic infarction in the adenoma.